American cities are now more integrated than they’ve been since 1910. Segregation rose dramatically with black migration to cities in the mid-20th century. On average, this rise has been entirely erased by integration since the 1960s.

All-white neighborhoods are effectively extinct. Fifty years ago, one-fifth of America’s urban neighborhoods had exactly zero black residents. Today, African-American residents can be found in 199 out of every 200 neighborhoods nationwide. The remaining neighborhoods are mostly in remote rural areas or in cities with very little black population.

Gentrification and immigration have made a dent in segregation. While these phenomena are clearly important in some areas, the rise of black suburbanization explains much more of the decline in segregation.

Ghetto neighborhoods persist, but most have declining populations. For every diversifying ghetto neighborhood, many more house a dwindling population of black residents.

The decline in segregation carries with it several lessons relevant to public policy debates, the authors noted. At its mid-century peak, segregation reflected the operation of both government and market forces. Beginning in the 1930s, federal regulations disfavored the extension of mortgage credit to homeowners in mixed-race neighborhoods. Restrictive covenants prohibited integration in some areas until the Supreme Court ruled them unenforceable in 1948. Decisions by public housing authorities and other agencies often reinforced existing patterns of segregation.

The decline in segregation can be partly attributed to the reform of these government practices and partly to changes in racial attitudes that can be considered both cause and consequence of policy change. The extension of mortgage credit also appears to have encouraged suburban integration; the list of cities with the largest declines in segregation since 2000 includes several caught up in the subprime housing bubble during the same period.

However, the end of segregation has not caused the end of racial inequality. Only a few decades ago, conventional wisdom held that segregation was the driving force behind socioeconomic inequality. The persistence of inequality, even as segregation has receded, suggests that inequality is a far more complex phenomenon.

Another finding relevant to current policy debates is that access to credit fosters mobility. At a time when proposed regulations threaten to eliminate the market for lending to marginal borrowers, it is important to recognize that there are costs and benefits associated with tightening credit standards, the authors noted.

In addition, the freedom to choose one's location has helped reduce segregation. Segregation has declined in part because African-Americans left older, more segregated, cities and moved to less segregated Sun Belt cities and suburbs. This process occurred despite some public attempts to keep people in these older areas.